Comparison of Spermatozoa Recovery Methods on Cauda Epididymal Sperm of Hanwoo Bulls

Comparison of two methods of extracting bull epididymal spermatozoa

Extraction of epididymal spermatozoa may be necessary to avoid losing valuable genetic material, for example, from individuals of rare breeds or endangered species, but the resulting sperm samples may be of poor quality. Two methods of extracting bull epididymal spermatozoa from slaughterhouse material were compared. The bulls were 16-23 months of age. Spermatozoa were extracted by making an incision one cm in length in the tail of the epididymis to allow the spermatozoa to flow out (method A), or by flushing the tail of epididymis (method B). The two methods were used for each bull, alternating between right and left epididymis, i.e. if method A was used for the left epididymis in Bull 1, it was used for the right epididymis in bull 2, etc. Sperm concentration in the extracted samples was adjusted to 69 × 106/mL in Andromed; the sperm sample was packed in 0.25 mL straws. After cooling for two h at 5 °C, the straws were placed 4 cm above liquid nitrogen for 20 min before transferring them to liquid nitrogen. Sperm motility, viability, reactive oxygen species, membrane integrity and DNA fragmentation were analysed in the fresh samples and again after thawing. The results for all parameters in fresh semen were not different between methods. Although sperm quality was lower in thawed samples than in fresh samples, there was no difference in sperm quality between the two extraction methods in the thawed samples. In conclusion, both methods are useful for the extraction of bull epididymal spermatozoa.

The Influence of Three Commercial Soy Lecithin-Based Semen Extenders and Two Spermatozoa Concentrations on the Quality of Pre-Freeze and Post-Thaw Ram Epididymal Spermatozoa

There are limited studies on the factors affecting the success of ram epididymal spermatozoa (REPS) cryopreservation. On this note, the current study assessed the influence of three commercial soy lecithin-based semen extenders, AndroMed® (AND), BioXcell® (BIO), and OviXcell® (OVI), and two concentrations (400 × 106 vs. 200 × 106 spermatozoa/mL) on the pre-freeze and post-thaw quality of REPS. The REPS were retrieved from nine adult rams' testes and diluted with each of the three extenders to both concentrations. Straws were frozen manually. Standard motility (SMP) and kinematic parameters (KPs) were assessed via a CASA, while spermatozoa viability, morphology, and acrosomal integrity were assessed via the Kovács-Foote staining technique. The concentration did not significantly affect the pre-freeze and post-thaw SMP and KPs of REPS. BIO and OVI had significantly higher pre-freeze and post-thaw BCFs, post-thaw VAP, and the percentage of all intact heads than AND. In contrast, AND had a significantly lower percentage of REPS with tail defects than BIO and OVI. The 400 × 106 spermatozoa/mL concentration resulted in a significantly higher percentage of all intact heads than the 200 × 106 spermatozoa/mL concentration. Freezing significantly increased tail defects and decreased the percentage of REPS with distal cytoplasmic droplets. The cryopreservation of REPS at the 400 × 106 spermatozoa/mL concentration is recommended. All three extenders must be optimized to preserve the viability, membrane integrity, and better normal morphology of REPS; the reason for increased tail abnormality after the freezing/thawing process needs to be studied.